(Si) _5-2y(AlP) _y alloys assembled on Si(100) from Al-P-Si ₃ building units

An original class of IV/III-V hybrid (Si) _5-2y(AlP) _y/Si(100) semiconductors have been produced via tailored interactions of molecular P(SiH ₃) ₃ and atomic Al yielding tetrahedral Al-P-Si ₃ building blocks. Extensive structural, optical, and vibrational characterization corroborates that these units condense to assemble single-phase, monocrystalline alloys containing 60%-90% Si (y = 0.3-1.0) as nearly defect-free layers lattice-matched to Si. Spectroscopic ellipsometry and density functional theory band structure calculations indicate mild compositional bowing of the band gaps, suggesting that the tuning needed for optoelectronic applications should be feasible.